In recent years, small portable apparatuses equipped with an image pickup device (camera module), such as mobile phones, have become widely popular, and taking pictures instantly with such small portable apparatuses has become a common practice. And for small image pickup devices incorporated in such small portable apparatuses, an image pickup lens that requires no driving of the lens for focusing is proposed in order to avoid an increase in the size (see Patent Document 1, for example).
In the image pickup lens described in Patent Document 1, an inner area and an outer area of at least one lens surface concentric with the optical axis have different curvatures, and when f1 is the focal distance of the entire system resulting from the curvature of the outer area and f2 is the focal distance of the entire system resulting from the curvature of the inner area, f1 and f2 satisfies the following conditional expression (6).0.3≦f2/f1≦0.9  (6)
And according to the configuration of the image pickup lens described in Patent Document 1, object points that are significantly different from each other in their object point distance can be imaged on the same image plane at the same time (i.e., object points that are significantly different from each other in their object point distance can be imaged at the same time without driving the lens for focusing).